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Posted By Topic: Maximum Demand

Jan 10 2018 08:28

I'm trying to figure out how much capacity to allow for a factory MSB.
I have been given a list of machinery intended to be installed in the factory.
I have power ratings for a dozen or so machines in different forms - kW, A and HP. All are 3 phase.
Is the best thing to do convert all of these to Amps and then follow Table C2?
No p.f has been given for equipment so should i assume unity for that?

Jan 10 2018 10:25

Yes, follow C2.

But don't assume unity PF, when you know there will be motors and other non-linear loads. You'll need to know, or guestimate, FLC values in amps.

Jan 10 2018 18:45

My experience for what its worth ... depending on the industry, most uncorrected power factors lie between 0.78 and 0.85, some exceptions being quarries, plastic injection molders etc that can go lower. If a lot of heating is involved, absolutely essential to identify type used, as these P.F. values can be as low as 0.65 (induction) or 0.99 (resistance type)Conveyors etc also affect overall values